J. Scott Hartley art links 

Fine Arts Museums of San Francisco
George Inness, 1894

J. Scott Hartley at the Smithsonian American Art Museum, Washington D.C.

 
National Art Databases and Museum Inventories:

Smithsonian Institution Art Inventories
List of works nationwide from two sources: the Inventory of American Paintings Executed before 1914 and the Inventory of American Sculpture (only a few percent of listings have an accompanying image)

 

Wikimedia Commons Image Database  

 

Union List of Artist Names (Getty Museum)  
Reference sheet with basic information about the artist and pointers to other references.